Rituximab versus tocilizumab in rheumatoid arthritis: synovial biopsy-based biomarker analysis of the phase 4 R4RA randomized trial
Authors: Felice Rivellese, Anna E. A. Surace, Katriona Goldmann, Elisabetta Sciacca, Cankut Çubuk, Giovanni Giorli, Christopher R. John, Alessandra Nerviani, Liliane Fossati-Jimack, Georgina Thorborn, Manzoor Ahmed, Edoardo Prediletto, Sarah E. Church, Briana M. Hudson, Sarah E. Warren, Paul M. McKeigue, Frances Humby, Michele Bombardieri, Michael R. Barnes, Myles J. Lewis, Costantino Pitzalis, Felice Rivellese, Giovanni Giorli, Alessandra Nerviani, Liliane Fossati-Jimack, Georgina Thorborn, Frances Humby, Michele Bombardieri, Myles J. Lewis, Patrick Durez, Maya H. Buch, Hasan Rizvi, Arti Mahto, Carlomaurizio Montecucco, Bernard Lauwerys, Nora Ng, Pauline Ho, Vasco C. Romão, João Eurico Cabral da Fonseca, Patrick Verschueren, Stephen Kelly, Pier Paolo Sainaghi, Nagui Gendi, Bhaskar Dasgupta, Alberto Cauli, Piero Reynolds, Juan D. Cañete, Julio Ramirez, Raquel Celis, Robert Moots, Peter C. Taylor, Chris J. Edwards, John Isaacs, Peter Sasieni, Ernest Choy, Charlotte Thompson, Serena Bugatti, Mattia Bellan, Mattia Congia, Christopher Holroyd, Arthur Pratt, Laura White, Louise Warren, Joanna Peel, Rebecca Hands, Gaye Hadfield, Costantino Pitzalis
Journal: Nature Medicine (2022)

Patients with rheumatoid arthritis (RA) receive highly targeted biologic therapies without previous knowledge of target expression levels in the diseased tissue. Approximately 40% of patients do not respond to individual biologic therapies and 5–20% are refractory to all. In a biopsy-based, precision-medicine, randomized clinical trial in RA (R4RA; n = 164), patients with low/absent synovial B cell molecular signature had a lower response to rituximab (anti-CD20 monoclonal antibody) compared with that to tocilizumab (anti-IL6R monoclonal antibody) although the exact mechanisms of response/nonresponse remain to be established. Here, in-depth histological/molecular analyses of R4RA synovial biopsies identify humoral immune response gene signatures associated with response to rituximab and tocilizumab, and a stromal/fibroblast signature in patients refractory to all medications. Post-treatment changes in synovial gene expression and cell infiltration highlighted divergent effects of rituximab and tocilizumab relating to differing response/nonresponse mechanisms. Using ten-by-tenfold nested cross-validation, we developed machine learning algorithms predictive of response to rituximab (area under the curve (AUC) = 0.74), tocilizumab (AUC = 0.68) and, notably, multidrug resistance (AUC = 0.69). This study supports the notion that disease endotypes, driven by diverse molecular pathology pathways in the diseased tissue, determine diverse clinical and treatment–response phenotypes. It also highlights the importance of integration of molecular pathology signatures into clinical algorithms to optimize the future use of existing medications and inform the development of new drugs for refractory patients. Biomarker analysis of the phase 4 R4RA trial identifies pretreatment synovial biopsy features selectively associated with response to rituximab or tocilizumab, and leads to the development of models that might predict treatment benefit in patients with rheumatoid arthritis